Translator – Data Members

The Translator will have these data members:

    Table *table                                  – pointer to Table object
    List<Token *> *rpn_list                       – translated tokens list
    List<Token *> op_stack                        – pending operators stack
    List<List<Token *>::Element *> operand_stack  – processed operands stack

The members table, op_stack and operand_stack members will be initialized by argument or automatically by the constructor.  Upon calling the start() function, the rpn_list will be initialized (master item allocated).

Simple expressions have the general form of operand bin-op operand bin-op operand. Also each operand could be a lone operand or the form unary-op operand (where there may be more than one unary operator). The Translator will be either expecting an operand or unary operator(s) in front of the operand or a binary operator. Therefore, there will be a data member indicating what state the Translator is currently in along with it's enumeration definition:

    enum State:
        Initial  – nothing processed yet
        BinOp    – expecting a binary operator
        Operand  – expecting a unary operator or operand
    State state  – current state of the translator

There may be states as more of the Translator is implemented. The state will be set to Initial by the start() function. Upon the first call to add_token(), the dummy Null token will be pushed to the op_stack and the state will be set to Operand to expect the first unary operator or operand.